CVE-2026-12345
Race condition in tempfile.TemporaryDirectory cleanup allows deleting files outside the temporary directory
CVSS Score
0.0
EPSS Score
0.2%
EPSS Percentile
7th
The cleanup of tempfile.TemporaryDirectory is vulnerable to a race condition. An attacker who can modify the tree during cleanup can replace a directory with a symbolic link, causing files outside of the temporary directory to be deleted or have their permissions and file flags reset, with the privileges of the process performing the cleanup. Note that platforms where shutil.rmtree.avoids_symlink_attacks is false, remain affected, and file flags may still be reset outside of the tree on all platforms.
| Vendor | python software foundation |
| Product | cpython |
| Published | Sep 29, 2026 |
| Last Updated | Oct 10, 2026 |
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Affected Versions
Python Software Foundation / CPython
0 < 3.12.15 3.15.0a1 < 3.15.0rc3
References
github.com: https://github.com/python/cpython/pull/157580 github.com: https://github.com/python/cpython/issues/157579 github.com: https://github.com/python/cpython/commit/5c20517a4fc56683efe63a7751020db9573f538d github.com: https://github.com/python/cpython/commit/458e7134a5af7f86aee9d21b51cf499b41aa4420 github.com: https://github.com/python/cpython/commit/e1f3590f155c6d66007e958c98c9d69316551993 github.com: https://github.com/python/cpython/commit/06ef3d43fdaf4da97af12fa694b4886092c4b970 github.com: https://github.com/python/cpython/commit/58ed0259cae509a19138795df302fe60b544dc74 openwall.com: http://www.openwall.com/lists/oss-security/2026/09/29/40
Credits
🔍 Bitshift (https://github.com/TheShiftedBit) Stan Ulbrych (https://github.com/StanFromIreland) Petr Viktorin (https://github.com/encukou)